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All-L-Leu-Pro-Leu-Pro: a challenging cyclization.

M E Haddadi·F Cavelier·E Vives·A Azmani·J Verducci·J Martinez
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Abstract

In this paper, we report the difficult synthesis of cyclo(Leu-Pro-Leu-Pro). While the cyclization of Leu-Pro-Leu-D-Pro did not cause problems, the all-L-peptide afforded cyclodimer rather than cyclotetrapeptide (cyclomonomer). A first attempt using our reversible backbone substitution methodology failed. However, we were successful in obtaining the desired cyclo(Leu-Pro-Leu-Pro) by decreasing the concentration. The ratio of cyclomonomer to cyclodimer was raised to 1:1.1 using BOP and 1:0.6 using HATU under our high dilution condition. The structures of the cyclopeptides were confidently assigned by electrospray ionization mass spectrometry and NMR.

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Cell DivisionChromatography, High Pressure LiquidHumansLeucineMagnetic Resonance SpectroscopyModels, ChemicalPeptidesProlineSpectrometry, Mass, Electrospray IonizationTemperatureTime FactorsTumor Cells, CulturedJournal Article

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M E Haddadi, F Cavelier, E Vives, A Azmani, J Verducci, J Martinez. 2000. All-L-Leu-Pro-Leu-Pro: a challenging cyclization.. https://doi.org/10.1002/1099-1387(200011)6%3A11%3C560%3A%3Aaid-psc275%3E3.0.co%3B2-i

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